-LRB- CNN -RRB- -- The Army sergeant who admitted to gunning down 16 civilians in a 2012 rampage through two villages near his outpost in southern Afghanistan is expected to take the stand at his sentencing hearing and will apologize .

Army Staff Sgt. Robert Bales pleaded guilty in June to more than 30 criminal charges , including 16 premeditated murder counts .

The plea spares the 39-year-old Bales the prospect of a death sentence in the killings . He now faces life in prison , but a jury of four officers and two enlisted personnel will decide whether he will have a chance at parole .

`` Yes , Bob will take -LRB- the -RRB- stand ... Yes , Bob will apologize , '' Bales ' lawyer , John Henry Browne said in an e-mail to CNN .

Bales admitted to slipping away from his outpost in southern Afghanistan and going on a house-to-house killing spree in two nearby villages in March 2012 , a massacre that further strained ties between American troops and their Afghan allies .

Afghanistan shootings Fast Facts

But he has not offered an explanation for his actions .

`` I 've asked that question a million times since then . There 's not a good reason in the world for the horrible things I did , '' Bales said when he pleaded guilty , according to Drew Mikkelson of CNN affilliate KING , who was tweeting from the courtroom .

Mikkelson also tweeted from the sentencing hearing , which began this week at Joint Base Lewis-McChord , near Tacoma , Washington .

So far , a number of Afghan civilians have taken the stand for the prosecution to talk about what they saw and survived .

Haji Mohammed Wazir lost 11 relatives -- his wife , mother , two brothers , a 13-year-old nephew and six of his seven children -- according to KING .

`` My life has never been the same , '' Wazir told the jury .

It 's been more than a year since the massacre , but Wazir said : `` I feel like it 's happening right now , '' the affiliate reported .

KING 's Mikkelson tweeted that a 12-year-old boy who survived the rampage testified about seeing his father and sister get shot .

Another witness broke down on the stand and cried out : `` For God 's sake , do n't ask me any more questions , '' Mikkelson wrote .

In addition to the murder counts , Bales pleaded guilty to six counts of attempted murder , seven of assault and the use of illicit steroids and alcohol . He pleaded not guilty to a charge of obstruction of justice .

Bales is a member of the Army 's 3rd Stryker Brigade Combat Team , an element of the 2nd Infantry Division . His attorneys have said the service made a mistake in assigning Bales to another combat tour despite evidence of post-traumatic stress disorder and a traumatic brain injury suffered during a combat tour in Iraq .

CNN 's Matt Smith contributed to this report .

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Army Staff Sgt. Robert Bales admitted to gunning down 16 civilians

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The plea spares the 39-year-old Bales the prospect of a death sentence

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A jury will decide whether he will have a chance at parole

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Afghan civilians have been called to testify about what they saw , survived